Digital information, and especially digital multimedia information such as digital video, digital audio, motion capture information, three-dimensional geometric model and/or animation data, still image data, or any sequence of digital still images, is generally quite large in size. For example, a frame of CCIR 601 format digital video is approximately 1 Mbyte in size and, at the typical rate of 30 frames per second, a one minute clip of CCIR 601 video requires approximately 1.8 Gbytes of storage space. Generally, while such information can be relatively inexpensively stored on magnetic tape or the like, it must be transferred to random access storage systems (RAID drives, RAM memory, etc.) for use with many systems such as multimedia authoring or editing systems. Unfortunately, the random access storage devices used in storage systems for digital information are generally quite expensive and thus systems which must deal with large amounts of such digital information, such as multimedia authoring and/or editing systems and the like, are correspondingly expensive and/or suffer constraints in the amount of information which can be worked with at any one time.
Attempts have been made in the past to reduce the required amount of storage for multimedia authoring and/or editing systems by managing the multimedia information stored and used in these systems. For example, if a video clip is no longer being used in a project, it can be purged from the storage system to free storage space for other information. Another strategy for managing storage demands is to perform an initial edit pass using lower quality digital information (e.g. using compressed digital video or audio) which requires less storage space. For example, digital video can be compressed at ratios of 5:1 or more with a commensurate reduction in the required storage space. This approach takes advantage of the fact that an editing process often begins by working with ten or twenty times as much material as will be used in the final cut. Once the final edits are made, the low quality digital information can be replaced on the storage device with only those portions of higher quality information which are needed to produce the final edit.
However, problems exist with the prior art attempts to manage storage demands. In general, it is difficult to track usage of digital information to determine the portions of this information which are not used and which therefore may be purged. To exacerbate this problem, the information may be available at two or more different qualities on the storage device. Also, when two or more different projects use the same information, redundant copies of this digital multimedia information are often maintained in the storage device thus occupying space which might otherwise be usefully employed and in the prior art it has been difficult or impossible to identify such redundancies. Further, it is impractical, if not impossible, in prior art systems to automatically replace lower quality digital information in an intermediate edit with higher quality information to complete a final edit.
It is desired to have a system, apparatus and method for managing the storage and use of digital information which overcomes these problems of the prior art.